A roller shoes is that the roller is installed on the shoe base in a detachable manner. A conventional roller shoes is constructed by that the roller installation groove is formed at the center of the rear of the shoe base, and a U shaped roller axle support, in which roller axle support grooves are formed at both sides thereof, is inserted and fixed into the roller installation groove. In addition, the roller rotates at the center of a roller.
Axle is engaged with the roller axle support and fixed at the shoe base. Further, the roller axle support is extruded from synthetic resin material.
Such conventional roller shoes can be used as general shoes and as roller shoes as well. That is, when the roller is not inserted into the roller shoes, this can be used as sole shoes, while when the roller is inserted into the roller installation groove on slope, this can be used as roller shoes.
The conventional roller shoes has a drawback in that since the roller axle of the roller is not confined in the roller axle support groove, which is open in semi-circular shape, and loosely inserted thereinto, and when a heel of the shoe is moved up, the roller axle is derailed from the roller axle support groove, and therefore the roller is deviated from the roller installation groove.
Moreover, since only one roller is mounted in rear of the shoe base, it is not possible to drive on plane earth as a roller skate, and a driving force per se such as mounting an ascending slope can not be obtained.
The previous structure of the roller is that the core and the tire are made as one body. That is, a plurality of stoppers are protrusively molded around the core. Such molded core is put into a casting mold to be connected with the tire, followed by introducing a fluid material of tire to be molded as one body. Thus, the stoppers are protrusively formed around the core such that, when the roller rotates, a slip in between the core and the tire can be prevented by the stoppers.
However, when the tire is used to a certain extent of time, it gets heated due to its friction against the ground and gets expanded. And the tire differs from the core in their coefficient of expansion by the difference in their material, thereby creating a gap in an abutment of the core and the tire.
In this case, the stoppers can prevent the slip i.e., derailment in a rotating direction, whereas they cannot perfectly prevent the slip in a direction along the roller axle.
U.S. Pat. Nos. 6,536,785 (Lee), 6,476,661 (Chang), 6,629,698 (Chu), 6,585,273 (Chiu), 6,572,120 (Chang), 6,631,911 (Chen et al.), 6,913,270 (Wang), 6,926,289 (Wang), and 6,913,269 (Wang) disclose a multifunctional roller skate, but those inventions are made of lot of metal parts. So they will get rusted from air moisture and ground water in a short time, thus having a short life-time. And the wheels are put into the midsole of the shoe base and, therefore, the wheels become very small, not leading to a fast running by free skating.
In case their invention is used as a running skate and if they have to use their roller as big as ours in size, the space to put the rollers into and to have other device for the rollers will become so big that the height of the midsole of the shoe becomes as high as women's high heel shoe, almost 80 mm high. And so their shoes bottom will be twice higher than ours, which is impossible to be used.
Adam's U.S. Pat. Nos. 6,979,003, 7,165,773, and 7,165,774 have 1 or 2 wheels only at the rear heel side. So they can run a short distance only by inertia force.
Further, the wheels are fixed. No convertible way to pull out the wheels for use as a normal shoe and to put them into use as a roller-shoe does exist. There is no brake. Therefore, it is very risky to run or to stop on a slope.
They can use their invention having the fixed wheels only for the purpose of normal shoe. So this can easily create a medical problem on ankle. Their cover over the roller is added onto the outsole, thereby making the outsole's rear area much higher. This also creates a medical problem on ankle.
In an embodiment of this invention, the height or the surface of the out sole of the shoe does not change, but maintain the same flatness even “with” or “without” the cover.
References CitedU.S. Patents5,398,970 AMarch 1995Tucky6,364,322 B1April 2002Lee6,394,468 B1May 2002Chiang et al.6,450,508 B1September 2002Chu6,476,661 B1May 2002Chang6,536,785 B2March 2003Lee6,572,120 B2June 2003Chang6,585,273 B2July 2003Chiu6,629,698 B2October 2003Chu6,631,911 B2October 2003Chen et al.6,634,656 B1October 2003Gervasoni6,698,769 B2March 2004Adams et al.6,739,602 B2May 2004Adams6,764,082 B2July 2004Roderick6,913,269 B2July 2005Wang6,913,270 B2July 2005Wang6,926,289 B2August 2005Wang6,979,003 B2December 2005Adams7,036,829 B2May 2006Maxwell et al.7,165,773 B2January 2007Adams7,165,774 B2January 2007Adams7,175,187 B2February 2007Lyden